Conference Coverage

Marijuana Use May Lead to Impaired Sleep Quality

And Other News From the 28th Annual Meeting of the Associated Professional Sleep Societies


MINNEAPOLIS—Marijuana use is associated with impaired sleep quality, according to research presented at the 28th Annual Meeting of the Associated Professional Sleep Societies. A history of cannabis use appears to be associated with an increased likelihood of reporting difficulty falling asleep, difficulty maintaining sleep, experiencing nonrestorative sleep, and feeling daytime sleepiness.

The strongest association was found in adults who started marijuana use before age 15. They were approximately twice as likely to have severe problems falling asleep (odds ratio [OR], 2.28), to experience nonrestorative sleep (OR, 2.25), and to feel excessively sleepy during the day (OR, 1.99). The only association found in participants who began using marijuana after age 18 was with severe nonrestorative sleep (OR, 1.67).

Results were adjusted for potential confounders, including age, sex, race or ethnicity, and education. Michael Grandner, PhD, Instructor in the Division of Mood and Anxiety Disorders at the University of Pennsylvania in Philadelphia, supervised the research.

The study involved adults between ages 20 and 59 who responded to the 2007–2008 National Health and Nutrition Examination Survey. A total of 1,811 participants reported a history of drug use. Information about cannabis use included any history of use, age at first use, and number of times used in the past month. The researchers considered sleep-related problems severe if they occurred at least 15 days per month.

Although the design of this study did not allow for an examination of causality, the results suggest that initiation of marijuana use in adolescence may impart a higher risk for subsequent insomnia symptoms. An alternative interpretation is that people who begin using marijuana earlier are more likely to experience insomnia for other reasons, such as stress. Insomnia may be one reason that people start or continue use, although the evidence suggests that marijuana probably is not effective for this indication.

“Marijuana use is common, with about half of adults having reported using it at some point in their life,” said Mr. Chheda. “As it becomes legal in many states, it will be important to understand the impact of marijuana use on public health, as its impact on sleep in the real world is not well known.”

Poor Sleep, Like Binge Drinking and Marijuana Use, May Predict Academic Problems
College students who sleep poorly are much more likely to earn worse grades and withdraw from a course than are peers who are healthy sleepers, according to a study presented.

Problems with sleep timing and sleep maintenance in college students are a strong predictor of academic problems, even after controlling for other factors that contribute to academic success, such as clinical depression, feeling isolated, and diagnosis with a learning disability or chronic health problem, according to the researchers. The study also suggested that sleep problems have approximately the same effect on grade point average (GPA) as binge drinking and marijuana use do.

Roxanne Prichard, PhD, Associate Professor of Psychology, and Monica Hartmann, Professor of Economics, both of the University of St. Thomas in St. Paul, Minnesota, analyzed data from the Spring 2009 American College Health Association National College Health Assessment to evaluate factors that predict undergraduate academic problems, including dropping a course, earning a lower course grade, and having a lower cumulative GPA. The researchers included responses from more than 43,000 participants in the analysis.

The negative effect of sleep problems on academic success was more pronounced for freshmen. Among first-year students, poor sleep—but not binge drinking, marijuana use, or a diagnosis of learning disabilities—independently predicted dropping or withdrawing from a course. Results were adjusted for potentially confounding factors such as race, gender, work hours, chronic illness, and psychiatric problems such as anxiety. “Well-rested students perform better academically and are healthier physically and psychologically,” said the investigators.

Student health information about the importance of sleep is lacking on most university campuses, according to Dr. Prichard. “Sleep problems are not systematically addressed in the same way that substance abuse problems are,” she said. “For colleges and universities, addressing sleep problems early in a student’s academic career can have a major economic benefit through increased retention.”

Can Treating Insomnia Reduce Suicide Risk?
Evidence suggests that suicides are significantly more likely to occur between midnight and 4 am than during the daytime or evening, researchers reported.

The weighted, scaled mean suicide rate per hour was 10.27% after midnight, and the rate peaked at 16.27% between 2 am and 2:59 am. In contrast, the mean suicide rate per hour was 2.13% between 6 am and 11:59 pm. When six-hour time blocks were examined, the observed frequency of suicide between midnight and 5:59 am was 3.6 times higher than expected.

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